Conduct a case-control investigation to study prospectively the effects of three oral contraceptives with identical estrogen and different progestational components of serum lipoprotein composition and function as well as on glucose metabolism. The study is designed to monitor changes in lipoprotein composition, glucose tolerance, and insulin secretion in young women who begin oral contraceptive use for the first time. Approximately 400 women will be studied, 100 for each of the drug groups, and a control group consisting of women who have chosen to use another forum of contraception. All four groups will be studied during a brief control period of four to six weeks, followed by a year long experimental period, during which time they will receive the assigned contraceptive preparations. After stopping oral contraception, subjects will be followed for a two month period to monitor the reversal of any observed change. All information collected and results from laboratory tests will be subjected to various statistical analyses.